Brilliant Animated GIF Shows The Rise Of High-Frequency Trading

Here's a great chart from Nanex, documenting the
rise of high frequency trading as fed in by main feeds from more
than a dozen major exchanges.

Nanex has color-coordinated the trades as they come in from the
different exchanges (PACF, for those trying to understand, is
NYSE Arca).

The GIF starts from January 2007 and continues for four years,
leaving out the trading seen just last week when a
computer glitch at Knight Capital Group erroneously executed
trades for more than half-an-hour.